No display on monitor

Have you tried putting the GPU in the lower PCIe slot? The lowest slot is connected
to the chipset rather than the CPU so if it works there then your CPU may have an
issue. If the GPU works in the bottom slot then I would recommend you return the
CPU for a replacement.

You can also double check to make sure your CPU cooler isn't mounted with too much
pressure. This can cause the CPU to warp in the socket and lift contact pads on
the edges of the CPU off the pins in the socket. If you are using a stock cooler
then this shouldn't be an issue but with many aftermarket coolers it is possible
to over tighten the cooler and cause issues. The general rule is even pressure on
all 4 corners and just to the point you start feeling a bit of resistance when
tightening then about half a turn more on each.

Edited by Xaltar - 21 Mar 2022 at 5:24pm

Great question

The CPU is so much more than just the central processing unit these days. There is
a PCIe lane controller, integrated memory controller, cache, northbridge and many
many more things integrated. All this integration needs to communicate with the
board, through the CPU socket and it's many pins. So a few pins not making contact
could effect any number of things. The system could be seemingly working fine
but then you discover you are missing a RAM channel or your PCIe slot is only
working at x8 rather than x16 or not working at all. Your system could even fail
to discover and recognize the RAM.

Each of the pins in the socket has a specific purpose and only a relative
handful of those are data bus lines for the CPU itself.

If the lowest slot also failed to work then I would check to make sure the GPU
is working (yes, I know you don't have another good system to test it in). You
may have to take it to a shop to check it for you. The lowest slot should work
if the only light you are getting is the GPU light. I am sorry but at this point
it looks like the GPU could be problematic. Sometimes what works in one system
won't work in another. Double check to make sure your GPU power cables are the
correct ones (6pin or 6+2 pin). Make sure the CPU power cable (4pin or 4+4 pin)
is connected to your board as well as the 24 pin main power cable.

You can also try pulling the whole thing out of the case and installing just the
CPU, GPU and one stick of RAM in the board while resting the board on the box it
came in (it's packaging). See if you can get it to boot outside the case. This
will rule out potential shorts between the board and the case etc. We call this
breadboarding when troubleshooting. Be meticulous and carful to follow all the
steps in the manual and if you still have an issue then it's time to start looking
at the components for the fault.

You can also try pulling the whole thing out of the case and installing just the CPU, GPU and one stick of RAM in the board while resting the board on the box it came in (it's packaging).

This will rule out storage and any components outside of the core ones needed
to get an image on your display. It's a fair amount of work but at this point
you need to rule out as much as possible and this is by far the easiest way to
do that.